Dual speed synchro unit



Aug. 31, 1948. H, 1 KEN-r 2,448,374

DUAL SPEED SYNCHRO UNIT BY/72:, W

ATTO R N EY Aug. 31, 1948. H J. KENT 2,448,374

DUAL SPEED sYNcmo UNIT Filed June '7,'1947 4 sheets-sheet 2 ATTORNEY Aug' 31, 1948- H. J. KENT DUAL SPEED SYNCHRO UNIT Filed June "7, 1947 4 Sheets-Shree?I 3 Aug. 3l, 1948. H. J. KENT I 2,448,374

` DUAL SPEED SYNCHRO UNIT Filed June '7, 1947 4 Sheets-Sheet 4 fill/111111111111lllllllllllz vlllllllllllzg l A IIIIIIIIIIHV//J INVENTOR /lfA/Ry J /fE/v ATTORNEY Patented Aug. 31, 1948 DUAL SPEED SYNCHRO UNIT Henry J. Kent, Teaneck, N. J., assigner to Kearfott Company, Inc., New York, iN. Y., a Acorporation of New York Application June 7, 1947, Serial No. 753,335

(Cl. '17k-252.)

4 Claims. l

This invention relates `to a synchro unit and more particularly to a unit including a servomotor anda `pair of synchro elements geared together for operation at selected speed ratios.

An l,object is to provide, in a unit of the above type, novel and vimproved Aclamping means for securing the various elements together.

Various other objects and advantages will be apparent as the nature of the invention is more fully disclosed.

`More specically, thepresent invention may be embodied in a unit including a pair of lsynchros of the wound `rotor type which are geared together so that one synchro constitutes a high speed `elementand the other synchro constitutes a low speed element, and a motor which is mounted in axial alignment with 'the synchros and `is geared thereto for driving the same to their designated positions. ,The motors and the synchros are provided with wound stators of magnetic material having Yaxially extending, aligned peripheral Ygrooves to :receive axially extending -clampin'g Ameans and electrical leads.

,Although the novel features Which'are charactcristic of `this invention are `pointed out more particularly in the claims, the nature of the invention will be better understood by referring to the following description, taken in Yconnection with Athe accompanying drawings in which a specic embodiment thereof has been vset forth for purposes of illustration.

In the drawings:

Fig. 1 is "an approximately `full sizedside elevation of a unit embodying the present invention;

Fig. 2 is an end elevation thereof;

Fig. '3 is an axial longitudinal section through the portion of the unit of Fig. l to the left of the line A-A taken on an enlarged scale;

Fig. 4 is a similar longitudinal section through the Aportion .of the unit of Fig. l to the right of line AA;

Fig. 5 is a detail View lof one of the clamping elements;

Figs. 6 and 7 are sections taken on the lines B-S and 'I-T, respectively, ofFig, 4;

Fig. 8 is a front elevation of the clamping ring for the high speed synchro;

Figs. '9 and 10 are sections Vtaken on the lines 9-9and I 0-I0,respectively, of Fig. 8;

Fig. 1l is a front elevation of the clamping ring for the low speed synchro; and

Fig. 12 is a section taken on the line I2-I2 of Fig. V11.

Referring to the drawings more -in detail, the unit Iis shown as `comprising a motor i9, 4a high.-

`2 speed synchro I0 fand a low-speed synchro `III which are mounted in axial alignment.

The high speed rsynchro I0 comprises a stationary ield I4 yof `magnetic material 'having slots I2 (Fig. 6) carrying a distributed Winding 15, and a rotor +8 -of magnetic material having slots carrying Va distributed Winding i1 and mounted on ashaft I8. The'stator I4 is provided with an axial -bore 'I9 `in which the rotor I6 revolves.

End plates 2B and 2l Aare-provided with-peripheral flanges 22 and '23, respectively, which -bear against the ends of the stator i4 and with hubs 24 and 25 having cylindrical surfaces A2b and '211 which are machined tot tightly within the "-bore i3 of the stator I4 vfor centering the rotor I'B in the stator. 'The-end -plates 20 and 27| carryibearings 28 and'28 in which the shaft I8 is journalled. The bearing 28,is positioned by a snap ring 3|.

The stator I 4 is provided with a plurality of axially extending lgrooves I3 (Fig. -6) spaced around the periphery Athereof and located -peripherally between the slots I2 so -that the thickness of the magnetic path is not reduced by the grooves.

The shaft I8 projects beyond the bearing 2S and carries an insulating bushing 52 von which slip rings -53 are mounted. The'bushingiEZand slip rings 253 are'of a size to vpass through Athe bearing 23 for purposes of assembly. The Shaft I8 also carries a gear 55 for connection'to the low'speed synchro II `tobe described.

A pair of U-shapedbrush ribbons 56 (Fig. 7) are attached to plates 60 which are screwed 'to an insulating ring f62. The`-brush ribbons '56 are bent back-at their ends to form brushes 63 which bear against the slip Y.rings 53. An insulating baiile -64 -is'disposed between the brushes 4to prevent accidental contact therebetween. Theinsulating ring 512 is secured 4against 'the end :plate 2l by screws.

A clamping ring 4l) (Figs f4 and 7-10) carries a pluralityof clamping arms 4I which span the stator I4 and are provided at their ends with hooks 42 which :engage an undercut annular shoulder 43 formed yon the flange 22 of the'end plate 20. The-clamping ring 40 carries set screws '44 which are journalled in'aligning recesses 45 in the end plate 2I and are provided vwith shoulders 4G which bear against the end plate fortightening the arml4| -so as to clamp the flanges 22 and 23 of the end plates 20 and 2l against the ends of the'stator I4. The shoulderf4'3 extends entirely around the -anges =22 so that the end 'plates-may be vclamped 'in any vdesired relative angular :position so as to provide maximum concentricity between the stator I4 and the rotor I6.

The low speed synchro I comprises a stator 10 formed of magnetic material having slots carrying a distributed winding 1| and a rotor 12 formed of magnetic material, having slots carrying a distributed winding 13. The rotor 12 is mounted on a shaft 14 which is journalled in bearings 15 and 16 mounted in end plates 11 and 18, respectively. The end plates 11 and 18 are provided with outer peripheral iianges 19 and 80 which bear against the ends of the stator I i and with inner hubs 8| and 82 having cylindrical surfaces 83 and 84 which are accurately machined to fit within anL internal bore 85 of the stator 10. The stator 10 is provided with peripheral grooves similar to the grooves I3 of the stator I4.

A ring 88 is attached to the end plate 11` byk suitable means, shown as studs 89, which carry a second ring 90 axially spaced from the ring 88 and having an axial opening 93 to receive the gear 55. The shaft 14 carries at its end a gear 9|. Gears 92 and 94 are carried bythe studs 89 and mesh respectively with the gears 55 and 9|.

The shaft 1'4 projects through the bearing 16 and carries an insulating bushing 95 on which slip rings 96 are mounted. The bushing 95 and slip rings 96 are of a size to pass through the bearing 16 for purposes of assembly. An insulating ring 91 carries plates 98 on which brushes 99 are mounted. An insulating baille is disposed between the brushes 99. 'I'he ring 91, plates 98, baffle |0| and brushes 99 are similar to the corresponding elements of the synchro I0 above described. The insulating ring 91 is secured to the end plate 18 by screws (not shown).

A clamping ring |00 carries a plurality of clamping arms |02 which span the stator 10 and end plates 11 and 18 and are provided with bifurcated ends |03 which are spaced to pass on opposite sides of the clamping arms 4| and are formed with hooks |04 which engage undercut grooves (Figs. 8 and 10) formed in ears |06 on the clamping plate 40 on opposite sides of the clamping arms 4|. The ring I 00 carries set screws |01 which enter aligning recesses |08 in the end plate 18 and :are provided with shoulders |09 which bear against the end surface of the end plate 18 for exerting clamping pressure on the arms |02.

The end plate 11 is provided with a peripheral positioning flange I0 which is adapted to engage the end plate 2| of the synchro I0 for positioning the two elements. with segmental slots to receive the arms |02.

A casing II I is positioned over the assembled unit and secured over peripheral flange 22 on the end plate 20.

The motor 9 comprises a stator |25 of magnetic material having slots carrying a distributed winding |26 and a rotor |21 of the squirrel-Shaped type including conducting rings |28 joined by conductors |29. The rotor |21 is mounted on a hollow shaft |30 which is journalled in a bearing |3| in an end plate |33 and in a bearing |32 in the end plate 20. The end plate |33 is provided with a peripheral flange I 34 which spans the stator |25 and engages the end plate 20.

The stator |25 is provided with peripheral grooves |35 similar to the groove I3 of the stator I4. Clamping rods |36 extend through holes in the end plate |33 and are threaded into a clamping ring |42 which bears against a ilange |43 on the end plate 20. The clamping rods |36 serve The ilange ||0 is formed 4 to secure the end plate |33 to the end plate 20 for supporting and positioning the stator |25 and rotor |21. The flange |34 of the end plate |33 seats in a recess |31 in a iiange |38 of the end plate 20 for positioning the motor element.

The hollow shaft |39 carries a gear |40 located beyond the end plate |33. A cap |45 is provided with a flange |46 seating against the end plate |33 to provide a gear chamber. The cap |45 carries a bearing |41 in which a shaft |48 is journailed. A disc |49 is located against a shoulder |53 on the cap |45 and is secured thereto by screws |50. The bearing |41 is locked by means of shims |5.| and a snap ring |52 engaging a recess in the cap |45. The ring |49 carries a plurality of studs |55 on which plates |56 and |51 are mounted. The plate |51 is provided with a central'opening |58 which is adapted to pass over the gear |40. A gear is mounted on the shaft |48. Gears |8| and |62 are mounted on a stud |55 and mesh respectively with the gears |60 and |40 for gearing the shaft |48 to the hollow shaft |30. The shaft |48 is provided with an extension |85 of reduced diameter which extends through the bore of the hollow shaft |30 and is keyed to the shaft I8 of the synchro I0 by means of a key |80. The shaft |48 is also provided with a shoulder |61 which positions the shaft against the disc |49. The end cap |45 is secured to the end plate |33 by a plurality of bolts |68 which extend through the cap |45 and are threaded into the end plate |33.

In assembling this unit the synchro I0 is rst assembled by positioning the end plates 2|) and 2| against the two ends of the stator I4, positioning the clamping ring 40 against the end plate 2| with the set screws 44 inserted in the aligning holes 45 in the end plate and engaging the hooks 42 of the arms 4| in the annular shoulder 43 of the end plate 20. The set screws 44 are then tightened for clamping the elements together.

The synchro is next assembled by positioning the end plates 11 and 18 against the stator 10 and locating the flange H0 of the end plate 11 against the end plate 2| of the synchro I0. The clamping ring |00 is then positioned over the end plate 18 with the set screws |01 engaged in the aligning recesses |08, and the hooks |04 of the arms |02 are engaged in the recesses |05 of the clamping ring 40. The set screws |01 are then tightened for clamping the unit in position as shown in Fig. 4.

The motor 9 is then assembled by assembling the end plates 20 and |33, the stator |25 and the rotor |21 and securing the same by means of the rods |36. The end cap |45 is then positioned over the end plate |33, the shaft |65 passing through` the hollow shaft 30, and sliding into the end of the shaft I 8. At the same time the gear |82 is brought into mesh with the gear |40. The end cap may be secured by the bolts |68.

The electrical connections from the rotor windings to the slip rings may be positioned in suitable recesses in the shafts I8 and 14, respectively. Leads ||8 from the windings of the synchro |0 may be positioned around the positioning ange ||0 in the space between the ears |06 of the ring 40 (Fig. 7) and may be positioned in certain of the spaced axial .grooves in the stator 10. Electrical leads I9 to the motor 9 may lie in certain spaced axial grooves of the stators I4 and 10 and may extend between adjacent ears |06 of the ring 49 so that all of the leads are contained Within the peripheral confines of the unit.

In the operation o f this device, the gear trains ,am-aw.

comprising fthe gears 155, "9| F82 and :T34 :may tbe selected to lprovide any ldesired ratiobetween the lowspeed synchro. ll and the high-speed synchro l0. Af'ratiolof `36:.1 smay, for example, be used. The low speed synchro .thus comprises: theprimary follower to followthesignal and the :high speed synchro vcomprises va .Vernier lfor "in-creasing the accuracy of =the unit. The *low speed synchro, however, :prevents r the Vhigh speed synchro from falling one or more complete lrotations f'outof registration withthe incoming signal.

The synchro elements have been shown as including wound rotors with distributed windings, but the structure may also be applied to rotors of the salient pole type or to brushless rotors. The stator windings may be of the two-phase or three-phase type and the rotor windings may be of the single phase, two-phase or three-phase type depending upon the use to which the unit is to be applied.

For operation as a servo, the synchros are electrically connected as control transformers to the corresponding synchros of a transmitter and the motor 9 is energized to drive the synchros I0 and I I to the designated angular position as indicated by the received signals. The clamping arms as shown may, of course, be applied to a double synchro unit and have been shown for purposes of illustration only as applied to a unit including a servomotor.

The unit above described is compact and may be assembled in a small size as indicated by Fig. l, The motor 9 may be designed to supply power to operate a suitable apparatus which is to be controlled by the incoming signal.

Although a specific embodiment of the invention has been shown for purposes of illustration, it is to be understood that the invention is capable of Various uses and that modications may be made therein as will be readily apparent to a person skilled in the art. The scope of the invention is only to be limited in accordance with the following claims.

What is claimed is:

1. A multiple synchro unit comprising a pair of synchro elements mounted in axial alignment, each of said elements comprising a stator of magnetic material, end plates engaging the ends of said stator, a shaft journalled in said end plates and a rotor carried by said shaft to rotate in the stator, gears interconnecting the shafts of the respective elements, a spacing flange extending between the inner end plates of said elements, and clamping means for said elements comprising a clamping ring adjacent the inner end plate of one of said elements, a plurality of clamping arms carried by said ring, spanning the stator of said one element and terminating in anges engaging the outer end plate of said one element, members carried by said clamping ring and bearing against said inner end plate for exerting clamping pressure on said arms, a second clamping ring positioned adjacent the outer end plate of the other of said elements and carrying clamping arms spanning said other element and said spacing flange and having bifurcated ends extending on opposite sides of said first arms and provided with ilanges engaging said rst clamping ring, and members carried by said second clamping ring and engaging said last mentioned outer end plate for exerting clamping pressure on said last arms to secure said other element to rst element.

2. A multiple synchro unit comprising a pair '6 ofusyn'chrolelements'mounted in axial alignment, feach of said :elements 'comprising 1a ystator of magnetic AmateriaLlerid .plates engaging the :ends of fsaid stator, a shaft Ljournalled in said rend platesanda rotor carried tiby v'said shaftto iroltate 'in 'the stator, gears interconnecting the shafts -oi' ith-e :respective elements, a spacing angezextending between the inner end plates of saidrelements, 'and clamping means for said elements ...comprising a clamping ring 'adjacent `the linner :end plate of one v`of :said elements, sa plurality of clamping arms carried by said ring and spanning the stator of said one element and terminating in hooks engaging the outer end plate of said one element, members carried by said clamping ring and bearing against said inner end plate for exerting clamping pressure on said arms, a second clamping ring positioned adjacent the outer end plate of the other of said elements and carrying clamping arms spanning said other element and said spacing ilange and having bifurcated ends extending on opposite sides of said rst arms and terminating in hooks engaging said first clamping ring, and members carried by said second clamping ring and engaging said last mentioned outer end plate for exerting clamping pressure on said last arms to secure said other element to the rst element.

3. A multiple synchro unit comprising a pair of synchro elements mounted in axial alignment, each of said elements comprising a stator of magnetic material, end plates engaging the ends of said stator, a shaft journalled in said end plates and a rotor carried by said shaft to rotate in the stator, gears interconnecting the shafts of the respective elements, a spacing flange extending between the inner end plates of said elements, and clamping means for said elements comprising a clamping ring adjacent the inner end plate of one of said elements, a plurality of clamping arms carried by said ring and spanning the stator of said one element, an annular shoulder formed on the outer end plate of said one element, hooks formed on the ends of said arms and engaging said annular shoulder, set screws carried by said clamping ring and bearing against said inner end plate for exerting clamping pressure on said arms, a second clamping ring positioned adjacent the outer end plate of the other of said elements and 4carrying clamping arms spanning said other element and said spacing flange and having bifurcated ends extending on opposite sides of said rst arms, said bifurcated ends being provided with hooks engaging said first clamping ring and -set screws carried by said second clamping ring and engaging said last mentioned outer end plate for exerting clamping pressure on said last arms to secure said other element to the rst element.

4. A servo unit comprising a pair of synchro elements and a -servomotor element mounted in axial alignment, each of said elements comprising a stator of magnetic material, end plates engaging the ends of said stator, a shaft `lournalled in said end plates and a rotor carried by said shaft to rotate in the stator, gears interconnecting the shafts of the adjacent elements, a spacing flange extending between the inner end plates of said synchro elements, a common end plate between said servomotor element and the adjacent synchro element, and clamping means for said elements comprising clamping rods spanning the end plates and stator of said servomotor element, a clamping Vagafiaa'm ring adjacent the inner end plate of said last synchro element, a plurality ofV clamping arms carried .by said ringand spanning the stator of said last synchro element, an annular shoulder formed on said common end plate, hooks formed on the ends of said arms and engaging said annular shoulder, set screws carried by said clamping ring and vbearing against said inner end plate for exerting clamping pressure on said arms, a second clamping ring positioned flo adjacent the outer end plate of the other of said synchro elements and carrying `clamping arms spanning said other synchro element and having bifurcated ends extending on opposite sides of `said first arms,.said bifurcated ends being provided with hooks engaging said rst clamping ring and set screws carried by said second clamping ring and engaging said last mentioned outer end plate for exerting clamping pressure on said last arms to secure said synchro elements.

HENRY J KENT. 

